Samuel Eto'o kisses his jersey after scoring for Internazionale during the Serie A match between Inter and Lazio in April. Photograph: Luca Bruno/AP

Anzhi Makhachkala have reached an agreement with Internazionale to sign the Cameroon striker Samuel Eto'o in a three-year deal that is expected to make him the world's best-paid player.

Reports in Italy say the Russian club will pay Inter €25m (£21.8m) for the 30-year-old forward and he is set to earn €20.5m (£17.9m) after tax per season.

Anzhi said: "Today an agreement was reached between the football clubs, Anzhi and Inter, for the transfer of Samuel Eto'o. The terms of the transfer are completely agreed on both sides.

"Anzhi expresses gratitude to the leadership of Inter Milan for their professional and constructive approach in the negotiations. Tomorrow the player will undergo a medical examination, following which the player will be awarded a three-year contract. On Thursday Samuel will arrive at the location of his new team and will begin preparations for the match against FC Rostov."

Anzhi's market consultant, German Tkachenko, led a delegation from the Russian club, who met their Inter counterparts on Tuesday to thrash out the deal.

Eto'o scored 21 goals in 35 Serie A appearances for Inter last season, having helped Barcelona to Champions League wins in 2006 and 2009, scoring in the finals against Arsenal and Manchester United.